WO2006075570A1

WO2006075570A1 - Plasma generating apparatus

Info

Publication number: WO2006075570A1
Application number: PCT/JP2006/300128
Authority: WO
Inventors: Masaru Hori; Hiroyuki Kano
Original assignee: National University Corporation Nagoya University; Nu Eco Engineering Co., Ltd.
Priority date: 2005-01-11
Filing date: 2006-01-10
Publication date: 2006-07-20
Also published as: JP2006196210A

Abstract

[PROBLEMS] To efficiently irradiate a region having a discretionary shape with plasma. [MEANS FOR SOLVING PROBLEMS] Electrodes (10A, 10B) are provided with a series of groove sections (11) on facing planes, respectively. An opening section (101) is formed by combining the electrodes (10A, 10B) and a jig (20) composed of an insulating material having a gas flow path (201) for generating plasma. Thus, when an alternating potential is applied to the electrodes (10A, 10B), hollow cathode plasma is generated in a groove section (11) of the electrode on a cathode side, and the plasma is applied on an object to be processed at an upper part in the drawing, with a flow of the gas for generating plasma. The region having a discretionary shape is efficiently irradiated with plasma by designing a region where the electrodes (10A, 10B) face each other, namely a shape of the opening section (101).

Description

Specification

Plasma generator

Technical field

[0001] The present invention relates to a plasma generator for injecting plasma into a region having a desired shape.

The present invention is particularly useful as a plasma generator used for surface treatment, film formation, and other processing.

Background art

In surface treatment using plasma and film formation and other processing, for example, a method in which plasma is jetted over the entire surface of a semiconductor wafer is well known. For example, surface processing by reactive ion etching and film formation by plasma CVD are well known.

[0003] In addition, so-called high-frequency holo-first sword plasma is also known as a technique for irradiating high-density plasma on the entire large-diameter wafer (Patent Documents 1 and 2).

Patent Document 1: JP-A-1-226147

Patent Document 2: JP-A-9-22798

Non-Patent Document 1: Applied Physics Letter, Vol. 85, 549-551 (2004)

Disclosure of the invention

Problems to be solved by the invention

[0004] Now, as plasma is applied to various treatments and processes, it has been required to irradiate plasma in a limited area under atmospheric pressure particularly efficiently. For example, when soldering external wiring to a printed circuit board, the soldered part may be cleaned using plasma. The soldering location is not limited to a striped, rectangular, or circular region, and the length and other dimensions vary depending on the location.

[0005] For example, when dielectric barrier discharge or streamer discharge is used, the discharge location becomes random, and it is very difficult to control such that a specific portion is irradiated with plasma. In addition, although microwave-excited plasma using a narrow gap electrode described in Non-Patent Document 1 can easily form the gap in a stripe shape or a circumferential shape, it is difficult to generate a plasma having a complicated shape.

[0006] Here, the present inventors flow plasma gas through the gap between two electrodes, The present invention was completed with the idea of generating a plasma on at least one surface of two electrodes through which plasma gas flows.

Means for solving the problem

[0007] In order to solve the above-mentioned problem, the means according to claim 1 is a plasma generator, and includes two electrodes used with a gap so as to form an opening having a desired shape. In addition, at least one recess is formed in a portion facing the gap between at least one of the electrodes. By injecting a gas that generates plasma into the gap from the side opposite to the opening, a hollow sword is formed in the recess. It is characterized in that plasma can be generated by discharge and plasma can be emitted from the opening.

[0008] Further, the means according to claim 2 is a plasma generator, and includes two electrodes used with a gap therebetween so as to form an opening having a desired shape, and at least one of the electrodes A series of grooves corresponding to the shape of the opening is formed in the part facing the gap of the gap. By injecting a gas that generates plasma into the gap from the opposite side of the opening, a hollow force is generated in the groove. It is characterized in that plasma can be generated by sword discharge and plasma can be emitted in the range of the shape of the opening.

The invention's effect

When the electrode is connected to a DC power supply or an AC power supply, a holo-force sword discharge is generated in the recess or groove on the electrode side to which a negative potential is applied, and high-density plasma is generated in the recess or groove. In the present invention, the plasma is emitted along a gas flow and irradiated in the shape of an opening. As described above, according to the present invention, by making the gap between the two electrodes have a desired shape, it is possible to easily irradiate plasma to a minute or specially shaped region particularly efficiently. In this case, a concave portion or a series of groove portions may be formed on the cathode side when a DC power source is used, at least one when an AC power source is used, and preferably both. It should be noted that the present invention includes incorporating the plasma generator of the present invention as a part of a processing apparatus or processing apparatus using plasma.

Brief Description of Drawings

FIG. 1 is a configuration diagram of a main part of a plasma generator according to a specific embodiment of the present invention.

[Fig. 2] Perspective before assembly to explain the shape of electrodes 10A and 10B and jig 20 Figure (2. A), perspective view after assembly (2. B).

[Fig. 3] Plan view (3. A), front view (3. B), 3. A cross-sectional view in the direction of arrow C of A (3. C), 3. B, D, E cross-sectional view (3. D and 3. E).

FIG. 4 is a diagram showing another electrode shape (opening shape).

FIG. 5 is a diagram showing another electrode shape (opening shape).

Explanation of symbols

[0011] 10A, 10B: Electrode

11: Recess or groove

101: Opening

20: Jig made of insulator

201: Gas flow path

20 It: Gas channel taper

202: Gas channel tip

203: Connection part

21 OA, 210B: Recess for mounting electrodes 10A, 10B

211: Projection

30A, 30B: Bonoleto

BEST MODE FOR CARRYING OUT THE INVENTION

[0012] In the present invention, plasma is generated in the vicinity of the opening, and the plasma is irradiated to the object to be calored disposed in the vicinity of the opening, so that no other plasma generation region is necessary. In order to form the opening, a jig consisting of two electrodes and an insulator to fix them is required. The simplest configuration is to provide a gas channel in the insulator and to provide two electrodes at the end of the gas channel. For example, in order to form a rectangular (stripe-shaped) opening, it is preferable to form four sides (surfaces) using a surface of two electrodes facing each other and a jig made of an insulator. A jig made of an insulator having a gas flow path may be constituted by one piece or a combination of a plurality of parts.

[0013] The electrode material is stainless steel, molybdenum, tantalum, nickel, copper, tungsten Or these alloys etc. can be used. If the thickness of the surface that forms the recesses that cause a hollow sword discharge is 1 to 10 mm in the direction of the gas flow path, it is good. For example, if the width and depth of the recess that generates a sword discharge is less than 1mm and about 0.5mm, it is good. The recess may be formed in a dot shape or a groove shape. The shape of the recess can be arbitrarily formed as a cylindrical surface, a hemispherical surface, a prismatic surface, a pyramid, or the like.

[0014] As a gas for generating plasma, a known gas can be selected according to an object to be processed.

For example, He, Ne, Ar and other rare gases, ammonia, hexafluoride, nitrogen trifluoride, fluorocarbons, and particularly fluorine compounds such as CF. Gas flow rate and supply volume

twenty four

Alternatively, the degree of vacuum can be set arbitrarily. In the present invention, the power source connected to the electrode is not a device that generates plasma by high frequency, and the power source connected to the electrode is arbitrary, such as direct current, alternating current, and the frequency is not limited.

Example 1

FIG. 1 is a diagram showing a configuration of a characteristic main part of a plasma generating apparatus according to a specific embodiment of the present invention. FIG. 1. A is an external view showing the vicinity of an opening 101, and FIG. B is a cross-sectional view along the gas flow path 201, and FIG. 1. C is a cross-sectional view showing details of the grooves 11 of the electrodes 10A and 10B.

[0016] As shown in FIG. 1. B, a jig 20 made of a cylindrical insulator having a gas flow path 201 as a center is combined with two bent plate-like electrodes 10A and 10B. At this time, as shown in FIG. 1.A, an opening 101 having four sides (surfaces) surrounded by the two electrodes 10A and 10B and the jig 20 is formed. The electrodes 10A and 10B are formed with two recesses 11 each having a width and a depth of 0.5 mm on the surfaces facing each other as shown in FIG. 1. C. The recesses 11 are formed on the long side of the opening 101. The groove has a length. The cross section of the recess 11 has a rectangular shape with one side removed. The shape of the gas flow path 201 is cylindrical in the vicinity of the connection portion 203 for introducing gas, and the cross section is rectangular at the tip end portion 202 via the taper portion 201t. The electrodes 10A and 10B are fixed to the jig 20 with bolts 30A and 30B, respectively.

[0017] When electrodes 10A and 10B are connected to an AC power source, a voltage is applied, and a gas for generating plasma is passed through the gas flow path 201 of the jig 20 to the opening 101, the electrodes 10A and 10B In the recess 11 on the side to which a negative potential is applied, it is emitted by a holo-power sword discharge. The generated electrons collide with the gas and plasma is generated with high density. The plasma generated by the holo-power sword discharge rides on the gas flow and is irradiated from the opening 101. As a result, plasma is efficiently irradiated to a narrow region facing the opening 101 of the workpiece.

FIG. 2 is a perspective view for explaining the shapes of the electrodes 10A and 10B and the jig 20.

2. A is a perspective view before assembly, and FIG. 2. B is a perspective view after assembly. As shown in FIG. 2. A, the groove 11 of the electrode 10B is a series of grooves corresponding to the longitudinal direction of the opening 101. The groove 11 of the electrode 10A is formed in the same manner. The tip 202 of the gas channel 201 of the jig 20 has a rectangular shape as shown in FIG. The jig 20 has a projecting portion 211 above the tip end portion 202 of the gas flow path 201 and a recess 210A for assembling the electrode 10A. Similarly, a recess 210B for assembling the electrode 10B is provided. A rectangular opening 101 is formed by the inner surface of the protruding portion 211 of the jig 20 and the electrodes 10A and 10B as shown in FIG.

FIG. 3 is a diagram for explaining the shape of the jig 20 in detail. FIG. 3. A is a plan view seen from the front end 202 side of the gas flow path 201, FIG. Fig. 3. C is a cross-sectional view in the direction of arrow C in Fig. 3. A. Fig. 3. D and Fig. 3. E are cross-sectional views in the direction of arrow D and E in Fig. 3. B, respectively. As shown in FIG. 2, the jig 20 is provided with a protruding portion 211 ahead of the rectangular tip 202 of the gas flow channel 201 on the rectangular parallelepiped having the gas flow channel 201, and is used for assembling the electrodes 10A and 10B. The concave portions 210A and 210B are provided, and a connecting portion 203 for introducing gas is provided. As shown in Fig. 3. C, 3. D and 3. E, the shape of the gas flow path 201 is cylindrical in the vicinity of the connecting portion 203 for introducing the gas, and the rectangular end via the tapered portion 201t It is part 202.

In each drawing of FIG. 3, the holes for assembling the bolts 30A and 30B and the threads of the connecting portion 203 for introducing gas are omitted. Also, the assembly of electrodes 10A and 10B is not limited to one with bolts 30A and 30B, respectively. For example, any known technique such as providing a gap width adjusting washer and a bolt of the opening 101 near the rectangular front end 202 of the gas channel 201 can be added or replaced. In addition, FIGS. 1 to 3 show the force that shows the “plasma generating part”, which is the main part of the plasma generating device. By incorporating this into the plasma generating device, the plasma generating device that enables various processings Can be configured. At this time, as shown in FIGS. 1 to 3, the jig 20 having the electrodes 10A and 10B fixed thereto is fixed by any means, the power source is connected, and the gas supply system is connected to the connection portion 203. It corresponds to the practice of the invention. For the convenience of explanation, a diagram with “opening facing upward” is shown, but it is natural that the present invention includes a configuration for generating downflow plasma that emits plasma downward.

[0021] The configuration in FIG. 1 is a force that combines two electrodes with a jig 20 made of an insulator having a gas flow path to form an opening. For example, as shown in FIG. Also, the structure in which the opening 101 is formed only by 10D is acceptable. In the configuration of FIG. 4, the recesses are formed on the surfaces of the electrodes 10C and 10D that form the opening 101 and face each other. When the recess is a continuous groove, the groove (recess) is formed like a star so as to correspond to the star shape of the opening 101. The shape of the jig having the gas flow path, the method for fixing the jig and the electrode, and the method for connecting the electrode and the power source are arbitrary.

[0022] In addition, the shape of the opening may be a saddle shape as shown in FIG. 5A or a stripe shape having a wide portion as shown in FIG. If the width of the opening varies depending on the location as shown in Fig. 5.B, increase the number of recesses formed on the facing surface of the electrode in the wide part, if necessary.

[0023] In Fig. 1, it is assumed that a plasma generating gas is introduced from below and the workpiece is disposed above the opening 101. However, the direction of the opening, that is, the direction in which the plasma is emitted is described. It is not limited to upward. FIG. 1 shows an embodiment for explaining the main part of the present invention, and the plasma generator may be configured with the openings in the lateral direction and the downward direction.

Industrial applicability

[0024] The present invention is suitable for plasma cleaning in a minute range. The present invention is also applicable to simple photolithography (etching) and film formation that do not use a photoresist.

Claims

The scope of the claims

[1] A plasma generator,

In order to form an opening having a desired shape, two electrodes are used with a gap interposed therebetween, and at least one recess is formed in a portion facing the gap of at least one of the electrodes,

By injecting a gas for generating plasma into the gap from the side opposite to the opening, it is possible to generate a plasma by a holo-force sword discharge in the recess and to discharge the plasma from the opening. A plasma generating apparatus.

[2] A plasma generator,

A series of grooves corresponding to the shape of the opening is formed in a portion of the electrode facing the gap of at least one of the electrodes so as to form an opening having a desired shape. Formed,

By injecting a gas that generates plasma into the gap from the side opposite to the opening, it is possible to generate plasma by a holo-force sword discharge in the groove, and it is possible to emit plasma in a range of the shape of the opening The plasma generator characterized by having performed.